134 



THE BOOK OF CHOICE FERNS. 



more delicate division and growth of the ultimate sections of the frond than 

 that of the common species, or in a greater foliaceous development. Ferns 

 partaking of the plumose character are usually either partially or entirely 

 barren, the reproductive vigour of the plant, exactly as is the case with 

 flowering plants bearing double flowers, being apparently affected by the 

 leafy development. It is now beyond dispute that if spores are not, or are 

 only very sparingly, formed, the reproductive powers of these barren plants 

 are much more developed in the production of bads on various parts of their 

 fronds. Various and conscientious experiments have conclusively proved 

 that the barren Scolopendrium erispum, for instance, is much more readily 

 propagated from sections of the underground stem than the fertile varieties. 

 Among the British Ferns naturally barren, the most striking instance is that 

 of the beautiful Welsh Polypody [Polypodium vulgare cambricum), which, 

 although grown in great quantities, and consequently under very different 

 circumstances, and subjected to various climatic conditions and influences, 

 has never, to our knowledge, been seen bearing any fertile fronds, either in 

 its natural habitat or under cultivation. The characteristic of permanent 

 barrenness is equally well illustrated in the case of the lovely frilled or 

 plumose form of the common Hartstongue, Scolopendrium vulgare erispum, 

 which, although grown in enormous quantities and under various conditions, 

 has invariably refrained from producing spores. There is, it is true, a form 

 called S. vulgare erispum fertile, but it is a totally different plant from the 

 above, its plumose character being a great deal less prominent than in the 

 variety erispum. The same comparative distinctions, as regards fertility 

 in relation to "plumation," are exemplified to a similar degree in Moore's 

 very plumose form of the Lacly Fern, which very seldom produces any 

 spores, and in Axminster's form of the same species, which is less plumose, 

 and is generally fertile. We have, year after year, carefully examined the 

 fronds of plants of Moore's variety growing under totally different con- 

 ditions, the result of our researches being that sometimes, but very 

 rarely indeed, a very limited number of spore-cases or sori were found — 

 not in sufficient quantity in any case to ensure the propagation of that lovely 

 variety exclusively from spores. The same remarks apply also to Aspidium 

 (Polystichum) aculeatum angulare plumosum, which partakes of the barren 

 character to an exactly similar degree. If a few spore -cases are produced, 



